The heart is actually (one, two, or three) pumps?
Which chamber receives blood from superior and inferior vena cava?
Which heart chamber receives blood form the pulmonary veins?
Which heart chamber pumps unoxygenated blood out the pulmonary trunk?
Which chamber pumps oxygenated blood out of aorta to the systemic circuit?
Intercalated discs have desmosomes for
strong connection, to transmit force, and to gap junctions for electrical communication btwn cells
Blood returning to the heart from the pulmonary circuit first enters the
The papillary muscles function to
prevent AV valves from reversing into the atria
What is not found in the mediastinum
Tetanic musc contractions dont occur in a normal cardiac muscle because
the refractory period lasts until the muscle relaxes
Excess fluid causes cardiac tamponade in the...
Blood leaves the right ventricle by passing through the
The AV valves permit blood flow
in one direction
The right ventricle pumps blood to the
right and left lungs
the left ventricle pumps blood to the
When a bld clot forms on a ruptured plaque in a coronary artery, the condition is known as
the muscle layer of the heart is
Oxygen is added to blood as it flows through the...
What part of the condition system initiates the depolarizing impulse which spreads throughout the heart?
What does the ECG wave tracing represent?
electircal activity in the heart
What does the QRS complex represent in the ECG wave tracing?
Contraction of the atria results from which wave of depolarization on the ECG tracing?
Which part of the intrinsic conduction system delays the impulse briefly before it moves on to the ventricles?
Different between cardiac and skel muscle is
Cardiac muscle cant be tatanized
In cardiac muscle, the fast depolarization phase of the action potential is the result of
increased membrane permeability of sodium ions
The long plateau phase of the cardiac muscle action potential is due to
calcium channels remaining open
The normal pacemaker of the heart is located in the
If the pacemaker cells in the SA node become more permeable to potassium ions
heart rate will decrease and cells will hyperpolarize
In the connection between the SA node and AV node becomes blocked
the ventricles will beat more slowly
The P wave of the electrocardiogram is a signal from
depolarization of the atria
During the T wave of the ECG, ventricles are
both repolarizing and relaxing
Pacemaker cells in the SA node
can spontaneously depolarize
A slower than normal heart rate is called
faster than normal heart rate is called
isovolumetric relaxtion and ventricular filling take place during
Filling od ventricles
passively in the ventricles through open AV valves
describe pressures in the atria and ventricles that would cause the opening of the AV valves
pressure in atria would be greater than the pressure in ventricles
What causes the aortic semilunar valve to close
greater pressure in the aorta than in the left ventricle
Phases of cardiac cycle in order
ventricular filling, contraction, ventricular ejection, isovolumetric relaxtion
Increased pressure in the ventricles would close what valves
AV valves only
What is the relaxed state of the ventricle called?
the one way nature of the left AV valve prevents blood flow from
the left ventricle of the left atrium
Majority of the ventricular filling occurs while the ventricles and atria are in what state?
relaxed, ventricular and atrial diastole
What describes the end diastolic volume?
the volume of the ventricle when it is most full
left ventricle filling occurs
while the AV valve is open
Decrease in left ventricular pressure at the end of ventricular systole causes
the semilunar valve to close
First heart sound is heard when the
AV valves close
During ventricular systole
AV valves are closed
With each ventricular systole
blood pressure increases
Contraction phase of the cardiac cycle is called
Which would increase cardiac output to the greatest extent?
increased heart rate and increased stroke volume
What would increase heart rate?
epinephrine and norepinephrine
How would an increase in the SNS increase stroke volume?
How would decrease in blood volume affect stroke volume and cardiac output?
volume and no change in cardiac output
heart rate is controlled by neurons of the cardiovascular center located in the
Cardiac output is increased by
Drugs that block the beta one adrenergic receptors will
decrease heart rate
activation of which kind of receptor causes rate to increase
beta one receptor